Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (Tables)

9 Months Ended

Sep. 30, 2019

Extractive Industries [Abstract]

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization

	September 30, 2019			December 31, 2018
	(in thousands)
Natural gas and oil properties:
Properties subject to depletion	$	10,277,879		$	10,974,929
Unproved properties		2,061,903			2,110,277
Total		12,339,782			13,085,206
Accumulated depreciation, depletion and amortization		(4,044,212	)		(4,062,021	)
Net capitalized costs	$	8,295,570		$	9,023,185

^{(a) Includes capitalized asset retirement costs and the associated accumulated amortization.}